Search

The photoluminescent (PL) properties of Sm3+-doped strontium hexaborate (SrB6O10) phosphors are significantly influenced by their crystallinity, phase and dopant concentration. To obtain a high brightness orange-red emitting SrB6O10:Sm3+ phosphor, a controlled and modified soluble-salt reaction method in the presence of a chelating agent (citric acid, C6H8O7) was used at ∼700 °C for about half an hour under an air atmosphere, which is otherwise only possible at very high (>1500 °C) sintering temperatures. The PL spectrum of the SrB6O10:Sm3+ phosphor produced strong and intense PL emission peaks centered at 560 nm (4G5/2 → 6H5/2), 596 nm (4G5/2 → 6H7/2), and 640 nm (4G5/2 → 6H9/2) under excitation of 400 nm (6H5/2→ 6H7/2). This is one of the very few reports that depicts the formation of more shallow traps in the lattice and the concentration quenching phenomenon was attributed to the non-radiative transfer of energy among Sm3+ ions via dipole–dipole interactions in the trap states. The optimized phosphor has noticeable reddish-orange Commission International de I'Eclairage color coordinates of (0.459, 0.337). The PL decay kinetics of the synthesized phosphor showed a biexponential decaying characteristic with an overall decay time of milliseconds. The presence of borate ions benefitted the thermal stability of the SrB6O10:Sm3+ phosphor as well. X-ray diffraction studies confirmed the phase purity, while scanning electron microscopy revealed the morphology to be an agglomerated rod-like structure. The PL intensity increased with increasing Sm3+ concentration and reached the optimum at 0.1 mol%. The obtained results clearly indicate that the SrB6O10:Sm3+ phosphor is a viable material for providing a red component for white-light emitting diodes (w-LEDs). [ABSTRACT FROM AUTHOR]